Towards a symmetric approach to high energy evolution: generating functional with Pomeron loops

Abstract

We derive an evolution equation for the generating functional which accounts for processes for both gluon emission and recombination. In terms of color dipoles, the kernel of this equation describes evolution as a classical branching process with conserved probabilities. The introduction of dipole recombination allows one to obtained closed loops during the evolution, which should be interpreted as Pomeron loops of the BFKL Pomerons. In comparison with the emission, the dipole recombination is formally $1/N_c^2$ suppressed. This suppression, nevertheless, is compensated at very high energies when the scattering amplitude tends to its unitarity bound.

Comments: 27 pages and 5 figures. Significantly revised version. To appear in Nuclear Physics A